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21.
Abstract. Haemagglutination activity was studied in last larval instars, pupae and adults of both sexes of the Culex pipiens mosquito complex. In females of Culex pipiens quinquefasciatus Say, an anautogenous member of C. pipiens complex, activity was detected in the homogenate of the head‐thorax complex, gut and remaining abdomen (after removing the gut), before and after sucking water, glucose solution or blood. Similar investigations were made in females of autogenous Culex pipiens molestus Forskal, a member of the same mosquito complex. The results were compared with data obtained for males of these subspecies, plus the larvae and pupae. The results show that haemagglutination activity in adult females depends not on the sucking of blood, but on the age of the females. In newly emerged females, the level of activity was very low, but after 24 h or 48 h of activity was highly enhanced, even in females that had no possibility to suck water or other liquids including blood. Furthermore, in C. p. molestus, the haemagglutination activity does not change in hungry or engorged females, and a high level of activity was found in the gut of last larval instars, a developmental stage that never takes blood. Treatment with methoprene reduces haemagglutination activity in both sexes, but 20‐hydroxycdysone application decreased activity in the gut of females. It is suggested that haemagglutination activity may be regulated indirectly by the endocrine system. The possibility that haemagglutination activity may depend on some aspect of the digestive system that has no direct connection to blood uptake is discussed. In addition, the activity may be important not only for the elimination of infections, but also for the processing of food and the utilization and transport of nutrients. 相似文献
22.
Jaroslav Votruba Jarmila Pazlarová Milada Dvořáková Kalju Vanatalu Libuše Váchová Marie Strnadová Helena Kučerová Jiří Chaloupka 《Applied microbiology and biotechnology》1987,26(4):373-377
Summary A mathematical model was formulated to describe the kinetics and stoichiometry of growth and proteinase production in Bacillus megaterium. Synthesis of the extracellular proteinase in a batch culture is repressed by amino acids. The specific rate of formation of the enzyme (r
E) can be described by the formula {ie373-1}, where k
2 and k
3 stand for the non-repressible and repressible part of enzyme synthesis respectively, k
S
2 is a repression coefficient and S
2 indicates the concentration of amono acids; the values of k
2 and k
S
2 depend on the composition of the mixture of amino acids. Even in a high concentration, a single amino acid is less effective than a mixture of amino acids. The dependence of the proteinase repression on the concentration of an external amino acid (leucine) follows the same course as its rate of incorporation into proteins, approaching saturation at concentrations higher than 50 M (half saturation approximately 10 M). However, the total uptake of leucine did not exhibit any saturation even at 500 M external concentration.Symbols
X
biomass concentration, g/l
-
E
proteinase concentration, unit/l
-
t
time, h
-
S
1
concentration of glucose, g/l
-
S
2
concentration of amino acids, g/l
-
specific growth rate, l/h
-
rE
specific rate of enzyme production, unit/g/h
-
k
1
growth kinetic constant, l/h
-
k
2
product formation kinetic constant (for non-repressible part of enzyme synthesis), unit/g
-
k
3
product formation kinetic constant (for repressible portion of enzyme synthesis), unit/g
-
k
S
1
saturation constant, g/l
-
k
S
2
repression coefficient for a certain amino acid or amino acids mixture, g/l 相似文献
23.
Vladimír Křen Jiří Ludvík Olga Kofroňová Jaroslava Kozová Zdeněk Řeháček 《Applied microbiology and biotechnology》1987,26(3):219-226
Summary The 550-day semicontinuous cultivation of Claviceps fusiformis immobilized in calcium alginate is documented. The vegetative mycelium from seed or from early-production submerged culture is the best choice for immobilization. No extracellular glucans are produced by immobilized cells. Immobilized spores give low yields of clavine alkaloids. Alginate concentrations in a range of 2%–4% do not influence yield and spectrum of alkaloids. The cytoplasm of the immobilized cells becomes condensed (after 3 days), polysaccharides disappear, and centres of lipid synthesis are formed in the cytoplasm. After 60 days the cells harbour a great number of lipid particles, mitochondria are diminishing and their cristae partly disappear, indicating a decreased respiration capacity. After 350–500 days the volume of most cells is increased many times and the cells are filled with large oval bodies of electrondense material. Chloramphenicol protects immobilized cultures against bacterial contamination. 相似文献
24.
Antibacterial, antifungal and antiprotozoal effects of nine mono- and bishydrazones of glycolaldehyde, glyoxal, methoxyacetaldehyde
and glutaraldehyde were studied using eight model organisms. It was found that bishydrazones are much more efficient antimicrobial
agents than monohydrazones in the case of all model microorganisms. 相似文献
25.
Marta Munzarová Daniela Zemanová Jan Kovařík Zdeněk Pačovský Aleš Rejthar Jiří Bártek 《Cancer immunology, immunotherapy : CII》1987,24(3):272-274
Summary Skin tests with autologous cholesteryl hemisuccinate (CHS)-treated and untreated cells were performed in ten metastatic melanoma patients. In the majority of cases evident reaction was noted with CHS-treated cells (9/10) while the reaction with untreated cells was mostly negative (7/10). Tumour cell suspensions used for skin tests were characterized for reactivity with monoclonal antibody TAL 1B5 detecting the HLA-DR alpha chain. There were no differences between CHS-treated and untreated cells with respect to HLA-DR expression and no correlation was found between grade of skin reaction to CHS-treated cells and the proportion of HLA-DR positive cells in the injected cell sample. 相似文献
26.
B. Koukalová J. Reich R. Matyášek V. Kuhrová M. Bezděk 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,78(1):77-80
Summary HRS60.1, a monomer unit (184 bp) of a highly repeated nuclear DNA sequence of Nicotiana tabacum, has been cloned and sequenced. Following BamHI digestion of tobacco DNA, Southern hybridization with HRS60.1 revealed a ladder of hybridization bands corresponding to multiples of the basic monomer unit. If the tobacco DNA was digested with restriction endonucleases which have no target site in HRS60.1, the larger part of DNA homologous to HRS60.1 remained as uncleaved relic DNA. These results suggest a tandem arrangement of this DNA repeat unit. Four other clones of tobacco nuclear DNA cross-hybridized with HRS60.1, thus forming a HRS60-family. Sequencing their inserts has shown their strong mutual homology. HRS60-family comprised about 2% of the nuclear genome of N. tabacum. Computer comparisons with other tandem plant-repeated DNA sequences could not detect any other homologous sequence. 相似文献
27.
Summary The threonine operon fromEscherichia coli was cloned in plasmid pBR322, subcloned into the shuttle vector pCEM300 and the resulting recombinant plasmid was transferred intoBrevibacterium flavum andCorynebacterium glutamicum. The expression ofE. coli threonine genes in these coryneform bacteria was demonstrated by complementing thethrA andthrB mutations and by assaying homoserine dehydrogenase activity. 相似文献
28.
29.
G. -J. A. Vidugiris A. V. Gudavičius V. J. Razumas J. J. Kulys 《European biophysics journal : EBJ》1989,17(1):19-23
Surface enhanced Raman scattering (SERS) of some enzymes (alkaline phosphatase, horseradish peroxidase and lactoperoxidase) and some amino acids (tryptophan, tyrosine and phenylalanine) on silver electrodes has been studied. The spectral band intensities of certain amino acids and amino acid residues were determined by their orientation on the surface and depended on the electrode potential (E).Abbreviations SERS
surface enhanced Raman scattering
- Trp
tryptophan
- Tyr
tyrosine
- Phe
phenylalanine
- E
electrode potential
- ORC
oxidation-reduction cycle 相似文献
30.
B Turyna T Ocha?ek 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》1989,27(3):161-167
Assessment of lymphocyte surface membrane integrity by means of trypan exclusion test and longer term survival studies based on 3HTdR uptake and Con A stimulation test were used to estimate effect of Staphylococcus aureus serine proteinase on human lymphocytes in vitro. At concentration of proteinase as high as 10 micrograms/ml, the percentage of trypan-stained lymphocytes increase with enzyme level. In contrast, decrease of 3HTdR level and Con A stimulation is already apparent at concentrations of proteinase ten times lower. Autologous serum exerts strong protective effect. Observed impairment is discussed as significant for local response in inflammation. 相似文献